Hydrodynamic modelling and outputs relating to fish farms: EIR release

Information requested

Information concerning the details of hydrodynamic modelling and outputs relating to a number of fish farm sites. You also asked for some specific details concerning the application of the model in general terms and in relation to the sites specified.

Response

The detail of your request is replicated below under the ‘Response to your request’ section along with our answers to the same.

As the information you have requested is 'environmental information' for the purposes of the Environmental Information (Scotland) Regulations 2004 (EIRs), we are required to deal with your request under those Regulations. We are applying the exemption at section 39(2) of the Freedom of Information (Scotland) Act 2002 (FOISA), so that we do not also have to deal with your request under FOISA.

This exemption is subject to the 'public interest test'. Therefore, taking account of all the circumstances of this case, we have considered if the public interest in disclosing the information outweighs the public interest in applying the exemption. We have found that, on balance, the public interest lies in favour of upholding the exemption, because there is no public interest in dealing with the same request under two different regimes. This is essentially a technical point and has no material effect on the outcome of your request.

Response to your request

You submitted a total of six questions. We are handling questions 1, 2, 5 and 6 under the EIRs and questions 3 and 4 are responded to generally out with those regulations. It is important that we make this distinction to you as this impacts upon your rights of review and appeal to the response given, which will only be valid to parts 1, 2, 5 and 6 of our response.

Specifically, your request stated:

Water Column Nutrient Levels
"In assessing water column nutrients e.g., Phosphorus and Nitrogen which could contribute to eutrophication and algal blooms, SEPA consults with Marine Scotland who undertake hydrographic modelling on our behalf. Marine Scotland’s consultation response received on 25 May 2021 confirmed that their modelling of the proposal indicated the degree of nutrient enhancement in the water column is predicted to be low and no objection was received. The Firth of Clyde is an uncategorised area under the Scottish Government (Marine Scotland) Locational Guidelines."

You then posed the following questions and requests for information:

1. Details of the hydrodynamic modelling of Little Cumbrae fish farm including the methodology, assumptions and the wider context as data inputs to the model’s prediction of low nutrient enhancement.

Marine Scotland Science holds no recorded information in relation to the methodology, assumptions and the wider context of the Open Water equilibrium concentration enhancement model used to determine the degree of nutrient enhancement from nitrogenous nutrients at open water sites, including Little Cumbrae.

2. Details of the modelling outputs for fish farms located at Ardentinny, Little Cumbrae, Big Cumbrae, Bute, North Kilbrannan and Millstone Point.

Ardentinny - MSS received a consultation request from SEPA in March 2019 in relation to the application for a fish farm site at Ardentinny. The proposed site sits within the boundary of the Locational Guidelines categorised area of Loch Long, and as such ECE modelling was undertaken using the model described in the LOCATIONAL GUIDANCE FOR FISH FARMING BASED ON PREDICTED LEVELS OF NUTRIENT ENHANCEMENT AND BENTHIC IMPACT (psu.edu). A copy of the output of the ECE model is provided and attached as Document 1. The ECE value recorded as the degree of enhancement from the total predicted biomass in Loch Long was 0.148μmol/L.

Little Cumbrae - MSS received a consultation request from SEPA in April 2021 in relation to the application for a fish farm site at Little Cumbrae. The output of the Open Water ECE model is not saved as a file output, but the value recorded as the degree of enhancement from nitrogenous nutrients was 0.4173μmol/L.

Big Cumbrae – MSS has not received a consultation for a site called Big Cumbrae, however we assume the reference is to the Cumbrae site. MSS received a consultation request from SEPA in April 2021 in relation to the application for a fish farm site at Cumbrae. The output of the Open Water ECE model is not saved as a file output, but the value recorded as the degree of enhancement from nitrogenous nutrients was 0.1951μmol/L.

Bute - MSS has not received a consultation for a site called Bute, however we assume the reference is to the South Bute site. MSS received a consultation request from SEPA in April 2021 in relation to the application for a fish farm site at South Bute. The output of the Open Water ECE model is not saved as a file output, but the value recorded as the degree of enhancement from nitrogenous nutrients was 0.1369μmol/L.

North Kilbrannan – MSS received a consultation request from SEPA in July 2018 in relation to the application for a fish farm site at North Kilbrannan. The output of the Open Water ECE model is not saved as a file output, but the value recorded as the degree of enhancement from nitrogenous nutrients was 0.1547μmol/L.

Millstone Point / North Arran – MSS received a consultation request from SEPA in May 2021 in relation to the application for a fish farm site at North Arran. The output of the Open Water ECE model is not saved as a file output, but the value recorded as the degree of enhancement from nitrogenous nutrients was 0.2693μmol/L.

Please refer to Table 5 on page 15 of the report LOCATIONAL GUIDANCE FOR FISH FARMING BASED ON PREDICTED LEVELS OF NUTRIENT ENHANCEMENT AND BENTHIC IMPACT (psu.edu) for information describing the range of values associated with predicted ECE for nitrogenous nutrients arising from fish farming. In describing the degree of enhancement, values between 0 and 1μmol/L are assessed to be low, between 1μmol/L and 3μmol/L medium, and between 3μmol/L and >10μmol/L high. The degree of enhancement in all cases detailed above was predicted to be low.

3. Do you calculate the combined effect of all these proposals at simultaneous peak biomass, or do you assess only one farm at a time?

The modelling undertaken by MSS for the sites in question that are located out-with Locational Guidelines categorised water bodies assess the ECE from the individual site being consulted on. Sites that are located within the boundaries of Locational Guidelines categorised water bodies consider the combined effects from all consented biomass (including the proposed site) within the specific water body (as described in the report accessed via the link in point 2) above).

4. Does the ECE assessment for each farm include the background nutrient level due to all the existing fish farms in the water body, operating at peak biomass?

The modelling undertaken by MSS calculates the ECE as the contribution from the site in question above background level. Please refer to the response at point 3) above for information on the approaches taken for sites in open water or sites within Locational Guidelines categorised water bodies.

5. When and where was the background level of DIN measured in the Greater Clyde?

MSS holds no information in relation to this query.

6. Were all existing farms at peak biomass at that time?

MSS holds no information in relation to this query.

While our aim is to provide information whenever possible, in this instance the Scottish Government does not have some of the information you have requested. Therefore we are refusing parts 5 and 6 of your request and aspects of parts 1 and 2 of your request, detailed below:

• with respect to part 1 - information in relation to the methodology, assumptions and the wider context of the Open Water equilibrium concentration enhancement (ECE) model and
• with respect to part 2 - information in relation to 'the output of the Open Water ECE model' where this has not been saved as a file.

We are refusing these sections of your request under the exception at regulation 10(4)(a) (information not held) of the EIRs.

Scottish Government does not hold this information specified above.

With respect to part 1 – the model was developed around 30 years ago and is now well established. We have been unable to locate documentation regarding the development of the model.

With respect to part 2 – the output of the open water ECE model is not saved as a file output, however the ECE value is recorded and has been provided in the response.

With respect to parts 5 and 6 – the information requested does not form part of the consideration of the modelling undertaken by MSS in response to consultations received from SEPA, therefore this information is not required or held by MSS.

This exception is subject to the 'public interest test'. Therefore, taking account of all the circumstances of this case, we have considered if the public interest in disclosing the information outweighs the public interest in applying the exception. We have found that, on balance, the public interest lies in favour of upholding the exception. While we recognise that there may be some public interest in information about ‘background levels of DIN; peak biomass; and information relating to the methodology, assumptions and wider context as well as output of the Open Water ECE model; as specified above, we cannot provide information which we do not hold.

About FOI

The Scottish Government is committed to publishing all information released in response to Freedom of Information requests. View all FOI responses at http://www.gov.scot/foi-responses.

FOI - 202100247510 - Information Released - Annex

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